Power Amplifier Speaker Protection Circuit Schematic

Power Amplifier Speaker Protection Circuit Schematic

While switching a power amplifier on, a loud thump sound is heard to sudden heavy discharge current through the speaker at the time of power on. This current may damage the speaker, especially in case of direct coupled amplifier.

PARTS LIST

R1

5KΩ Preset

C1

1000µF 25V

C2

0.1µF (104)

D1

IN4001

Q1

BC107

RL1

9V 500Ω Relay

LS1

Speaker

The circuit given here protects speakers from the current surge. When the amplifier is off, relay switch is also off. When the amplifier is switch on, R1 and Ci provide delay of a few seconds to switch the transistor on which energizes the relay.